Gold in Electronics

The concentration of free electrons in gold metal is 5.90×1022 cm−3. Gold is highly conductive to electricity, and has been used for electrical wiring in some high-energy applications (only silver and copper are more conductive per volume, but gold has the advantage of corrosion resistance). For example, gold electrical wires were used during some of the Manhattan Project’s atomic experiments, but large high current silver wires were used in the calutron isotope separator magnets in the project. Though gold is attacked by free chlorine, its good conductivity and general resistance to oxidation and corrosion in other environments (including resistance to non-chlorinated acids) has led to its widespread industrial use in the electronic era as a thin layer coating electrical connectors of all kinds, thereby ensuring good connection. For example, gold is used in the connectors of the more expensive electronics cables, such as audio, video and USB cables. The benefit of using gold over other connector metals such as tin in these applications is highly debated.

Gold connectors are often criticized by audio-visual experts as unnecessary for most consumers and seen as simply a marketing ploy. However, the use of gold in other applications in electronic sliding contacts in highly humid or corrosive atmospheres, and in use for contacts with a very high failure cost (certain computers, communications equipment, spacecraft, jet aircraft engines) remains very common.[57] Besides sliding electrical contacts, gold is also used in electrical contacts because of its resistance to corrosion, electrical conductivity, ductility and lack of toxicity.[58] Switch contacts are generally subjected to more intense corrosion stress than are sliding contacts. Fine gold wires are used to connect semiconductor devices to their packages through a process known as wire bonding. Gold

Gold is not an especially good conductor at all, though it is better than aluminum but not per unit weight due to its much higher density. It is very expensive, but compared to the cost of transport to the Moon from Earth, the cost is not significant. Gold is usually only used as a conductor in very specialized applications such as very fine wires like those used to wire bond integrated circuits to their lead frames. A more important everyday use of Gold is in connectors

For connectors gold reigns supreme for several reasons
1. It doesn’t tarnish (important on Earth, important indoors on Luna) 2. It is soft, so you can make the connectors tight and they dig into each other forming a good connection. Gold is not known to be available on the Moon.

Uses of Gold in Electronics

The most important industrial use of gold is in the manufacture of electronics. Solid state electronic devices use very low voltages and currents which are easily interrupted by corrosion or tarnish at the contact points. Gold is the highly efficient conductor that can carry these tiny currents and remain free of corrosion. Electronic components made with gold are highly reliable. Gold is used in connectors, switch and relay contacts, soldered joints, connecting wires and connection strips.

A small amount of gold is used in almost every sophisticated electronic device. This includes: cell phones, calculators, personal digital assistants, global positioning system units and other small electronic devices. Most large electronic appliances such as television sets also contain gold.

One challenge with the use of gold in very small quantities in very small devices is loss of the metal from society. Nearly one billion cell phones are produced each year and most of them contain about fifty cents worth of gold. Their average lifetime is under two years and very few are currently recycled. Although the amount of gold is small in each device, their enormous numbers translate into a lot of unrecycled gold. Properties of Gold

Khrysos (Gold) is a child of Zeus; neither moth nor rust devoureth it; but the mind of man is devoured by this supreme possession. – 5th century Greek fragment.

The crystal structure for metallic gold is face centred cubic. This crystal structure contributes to gold’s very high ductility since the lattices are particularly suitable for allowing the movement of dislocations in the lattice. | An unparalleled combination of chemical and physical properties make gold invaluable to a wide range of everyday applications. One of the most important of these properties is gold’s virtual indestructibility. Gold is the most non-reactive of all metals. It is called a “noble” metal (an alchemistic term) because it does not oxidize under ordinary conditions, meaning that it will never rust and never tarnish.It will, however, dissolve in aqueous mixtures containing various halogens such as chlorides, bromides, or some iodides. It will also dissolve in some oxidizing mixtures, such as cyanide ion with oxygen, and in aqua regia, a mixture of hydrochloric and nitric acids. Gold is only 2.5 on the Mohs scale of hardness – about the same as a fingernail. Pure gold is so soft and malleable that a strong man can squeeze it and shape it.

Therefore, gold could be used by artisans around the world for as far back as time can tell. Gold’s physical properties of high electrical conductivity and chemical inertness make it an excellent and reliable conductor, particularly in harsh environments, where temperatures can range from -55°C to 200°C. The use of gold in circuitry ensures reliability of equipment operation, particularly in the vital activation of safety airbag mechanisms in motor vehicles or deployment of satellites and spacecraft.No other metal is as ductile or as malleable as gold. A single ounce of the metal can be drawn into a wire five miles long. Gold can be hammered into sheets so thin that light can pass through. High purity gold reflects infrared (heat) energy almost completely, making it ideal for heat and radiation reflection. Gold-coated visors protected astronauts’ eyes from searing sunlight on the Apollo 11 moon landing. Gold is also an excellent conductor of thermal energy. It is used in many electronic processes to draw heat away from delicate instruments. For example, the main engine nozzle of the space shuttle uses a 35% gold alloy.